1. Field of the Invention
The present invention relates to a display device for displaying different images on one display screen in a plurality of directions, respectively.
2. Description of the Related Art
Conventionally, there has been proposed a display device capable of displaying different images on one display screen in a plurality of directions, respectively. Such a way of displaying is also referred to as “DV (dual view) display”. FIG. 11 is a cross sectional view schematically illustrating one example of such a display device. The display device shown in FIG. 11 includes a display panel 110, a barrier section 120, a backlight 130, and polarizing plates 141 and 142.
The backlight 130 includes a light source 131 and a reflecting section 132. The light source 131 emits light, and the reflecting section 132 reflects the light, with the result that light is irradiated onto the display panel 110. The display panel 110 is an active matrix liquid crystal display panel in which a liquid crystal layer 113 is sandwiched between a TFT substrate 111 and a CF substrate 112 arranged face to face with each other.
Provided on the TFT substrate 111 are a plurality of data signal lines and a plurality of scan signal lines respectively crossing the data signal lines. For combinations of the data signal lines and the scan signal lines, pixels are respectively provided (none of them is illustrated). Further, each of the data signal lines is connected to a source driver, and each of the scan signal lines is connected to a gate driver (none of them is illustrated). With this arrangement, when driving voltages are applied independently to the pixels, alignment conditions of liquid crystal molecules in pixel regions of the liquid crystal layer 113 are changed. In this way, a display operation is carried out.
The pixels are arranged in such a manner that pixel columns L and pixel columns R alternate with each other. Each of the pixel columns L extends in the direction in which the data signal lines extend and is used to display an image to the left side (image display for the left side with respect to the display device). Each of the pixel columns R is used to display an image to the right side (image display for the right side with respect to the display device).
Meanwhile, on the CF (color filter) substrate 112, a color filter layer (not shown) is provided.
The TFT substrate 111 and the CF substrate 112 have surfaces opposing to each other and provided with alignment films (not shown) having been subjected to alignment treatments carried out in directions orthogonal to each other. The alignment films have been subjected to a rubbing treatment carried out in a direction parallel to the surfaces of the substrates respectively.
The polarizing plate 141 is provided on the backlight 130 side of the TFT substrate 111 such that the absorption axis thereof is parallel to the direction in which the alignment treatment has been carried out with respect to the alignment film provided on the TFT substrate 111. Further, the polarizing plate 142 is provided on the side opposite to the display surface side (backlight 130 side) of the barrier section 120 such that the absorption axis thereof is orthogonal to the absorption axis of the polarizing plate 141. With this arrangement, driving voltages to be applied to the pixels are varied such that an image can be displayed on each of the pixel columns in its display direction.
The barrier section 120 is made up of a barrier glass 121, barrier light-blocking layers 122, and an adhesive layer 123. The barrier light-blocking layers 122 block light irradiated from the backlight 130 and having passed through the display panel 110. The adhesive layer 123 is formed on the barrier glass 121 so as to cover the barrier light-blocking layers 122, thus adhering the barrier section 120 to the display panel 110.
Further, the barrier light-blocking layers 122 are provided in lines in a stripe manner so as to correspond to the pixel columns respectively. That is, the barrier light-blocking layers 122 are provided to block light, irradiated from the backlight 130 and having passed through the pixel columns, such that the pixel columns L for the left side can be viewed from the left side with respect to the display device but cannot be viewed from the right side and the pixel columns R for the right side can be viewed from the right side with respect to the display device but cannot be viewed from the left side. With this, the display device is capable of displaying different images for the left side and the right side with respect to the display device respectively (DV display).
For example, Japanese Tokukai 2000-137443 discloses a display device used in a vehicle to simultaneously present different information to a driver and one in the passenger seat via a single display screen.
However, it is found that the display device suffers from such a problem that, e.g., an image for the passenger seat side overlaps with an image for the driver seat side and the overlapped images are therefore viewed and recognized, i.e., suffers from occurrence of “cross talk”.
Specifically, a barrier light-blocking layer formed in the same way as a resin light-blocking film for a color filter does not sufficiently block light of an image to be displayed for the passenger seat side, with the result that the light is leaked to the driver seat side. Further, a barrier light-blocking layer constituted by a metal light-blocking film unnecessarily reflects light, with the result that light of an image to be displayed for the passenger seat side goes into the driver seat side. Accordingly, overlapped images are viewed and recognized.
In order to solve the problem, the inventors of the present application discovered the need for a display device that is capable of displaying different images to a plurality of different viewpoints to have a function of separating images so as to prevent irradiated light in a certain display direction from leaking in other display directions.